An I. S. machine includes a plurality (usually 6, 8, 10 or 12) of identical sections. Each section has a blank station including a mold opening and closing mechanism having a pair of opposed mold arms which is displaceable between mold open and mold closed positions. A mold arm supports a number of inserts on which are placed anywhere from one to four blank mold halves. Each section also has a blow station including a similar mold opening and closing mechanism.
U.S. Pat. No. 5,865,868 illustrates a conventional mold open and close mechanism wherein the mold arms are supported for axial displacement. Mounted on the arm are upper and lower inserts, which will hold one half of each of the required molds pairs. In a triple gob application, an insert may have a first insert portion to support two mold halves and a second insert portion to support one mold half with the first insert portion being mounted relative to the second insert portion to equalize the clamping forces when the molds are closed.